NCIS and the Unexpected Teacher
by flootzavut
Summary: For the NFA "AU Times Two" challenge, also a sequel to my Harry Potter crossover NCIS and the Mysterious Door. The mysterious door reappears - why? What will the MCRT find if they head down the tunnel again?
1. Chapter 1

Sequel to "NCIS and the Mysterious Door" for the NFA AU x 2 challenge.

Second AU will become evident as time goes on :)

**_GIBBS_**

"Boss?"

Gibbs looked up. "Yeah, McGee?"

"There's something, uh, downstairs."

He waited. McGee's gaze briefly flickered over towards Tony and Ziva, both hard at work - or at least well occupied. Tony was staring at his computer screen with the intense concentration that usually meant he was playing whack-a-terrorist.

"What's up, Tim?"

The unaccustomed use of his given name was enough to bring McGee's attention back, though he still looked deeply uncomfortable. "You know that... incident... a few months ago?" His eyes widened dramatically and he lowered his voice. "The one we don't talk about?"

Suddenly McGee's expression started to make sense. _Oh. Damn_. That mysterious door, that inexplicable tunnel, and the things they'd found at the end of it that had made even less sense. It had been a long and confusing night.

The next morning he'd been able to convince himself that it was some kind of dream or a symptom of sleep deprivation till he got into work. Then he'd seen McGee's glazed expression, the brand new furrows in Ducky's forehead...

It had taken the rest of the day to decide that it was probably a mass hallucination (he didn't know if that was possible, frankly didn't care), and several weeks to push it so far to the back of his mind that it was almost forgotten. Almost.

"Uh huh?"

McGee swallowed nervously, as if he thought Gibbs might blame him for whatever weirdness had turned up in the evidence garage this week. "The door..."

_Crap_. He glanced towards the huge windows. Definitely daytime. Unless this was a recurring dream and he was actually on his couch at home. He could hope, right?

He sighed. "OK. OK." He collected his thoughts for a moment, then stood up. "Tony? Ziva? Grab your..." He paused. They were only going downstairs, but... "With me. And bring your sidearms."

McGee looked even less happy. "Boss, is that a good idea?" He said it quietly, but not quietly enough.

"Crime scene, McProbious." Tony delivered a slap to the back of Tim's head. Just a light one - he knew Gibbs would exact vengeance if he pushed his luck. "That means federal agents are a _good_ thing."

McGee shot a pleading look at Gibbs, who shrugged. If they were imagining things, a couple new pairs of eyes on the situation might help reality assert itself. If they weren't...

He shook his head. He'd worry about that if they had to. "Tim, stay here - do some research on the- for the... Just figure it out OK?"

"OK boss." McGee actually looked relieved for a moment. Then suddenly a little defiant, too. "I'll get Abby to help me."

Gibbs nodded, and even smiled to himself. Trust Tim to want to be sure and protect Abby from the weirdness. Two of his favourite scientists... and they always stuck together.

He walked off towards the back elevator, then turned back to Tony and Ziva, who looked mildly surprised at the direction he was taking. "You comin'?"


	2. Chapter 2

**_TONY_**

Gibbs was glaring at the door as if it had personally offended him. And maybe it had, Tony reflected. A door that just _appeared _in the evidence garage? That was definitely a Bad Thing, capital letters and all. What was weirder was that Gibbs was undeniably pissed off, but apparently not at all surprised. Reading his moods was a necessary survival trait on the team, and Tony was reasonably sure his conclusion was accurate. Granted, it took a lot to surprise the old man these days, but this was strange enough that it merited some reaction other than anger - didn't it?

Tony had tried to lighten the atmosphere with a joke or two, but had wilted when the glare had been turned on him for a moment. Ziva had examined the door minutely, then asked Gibbs what felt like several bajillion questions, none of which had gotten a reaction never mind an answer out of him.

Ziva could be particularly stubborn and sometimes nosy, given the right situation, and she'd quizzed Tony like that a time or two, but he'd never seen her turn her machine gun interrogation technique on the boss. He couldn't decide what was more unnerving, her single minded determination to get some information, any information, or Gibbs' absolute indifference.

Finally, and with no obvious prompt, Gibbs got up from the filing cabinet he'd been leaning his backside on and approached the door. It was metal and decidedly ordinary looking, all things considered. If a door was gonna materialise out of nowhere, you'd think it'd have the decency to look a little sinister or mysterious, but no.

Gibbs looked at it for a moment, then ducked to one side to use the iris scanner. After a moment the door swooshed open, and for the first time since they'd seen the door he looked a little surprised.

_Interesting_.

Tony opened his mouth again to ask some of the many questions teeming through his mind - and out of the corner of his eye, he could see Ziva doing the same - when Gibbs shocked him by stepping _through_ the door.

"Boss!"

"Gibbs!"

They both yelled in alarm at the same moment. Gibbs looked round at them, seemingly unruffled. "What?"

He sounded his usual impatient, mildly pissed self. That was oddly reassuring.

"Boss, it could be dangerous. You can't just... wander off into some spooky..." Tony waved his arms around as the words ran out. "We're not gonna... It's not... It's not safe."

"Tony is right." Ziva at least had the grace not to sound surprised at that, or to add the 'for once' he suspected she was thinking. "Gibbs, it is not wise to use this door, we do not know how it got here or where this-" she peered around him "-tunnel might lead. It is a prescription for calamity."

"I think she means a recipe for disaster, boss."

Gibbs propped himself up against the doorframe, half in, half out. "Come and see." He hitched a shoulder. "Nothin' in here to worry about. Besides, I've done this before." A little smirk.

Tony blinked. _The sly old fox._ They should've known. Gibbs knowing more than he would let on? Hardly a new experience. How the heck he could have prior knowledge of this, Tony couldn't - or didn't want to - imagine. But it figured.

"Care to elaborate, boss?"

Gibbs shrugged again. "Come and see." He turned and stepped down into the strange blue semi-darkness.

Ziva and Tony stared after him and then looked at each other.

"We cannot let him go alone," she said.

Tony grimaced. "Guess not." He shrugged, summoning up his best Gibbs impression. "Well, you heard the man. Let's go see."


	3. Chapter 3

_**GIBBS**_

Once the initial shock had worn off, Tony had gone back into motormouth mode. Gibbs was pretty certain it was mostly to avoid having to actually think too hard about the strangeness of what was happening, and he could somewhat sympathise. At the same time, he really wished they had Abby or Ducky or someone with them, someone who could answer Tony's incessant questions without feeling the desire to head slap him into oblivion.

He was almost surprised by how much he'd remembered about their last trip through that damn door. He hadn't done as good a job forgetting it as he'd thought, despite his best efforts, and Tony had dragged a lot of details out of him.

"So you're telling me that you ended up investigating a murder in a castle in Scotland that's also a boarding school for witches and wizards?"

Gibbs had lost count of the number of times Tony had asked that question, phrasing it in a variety of ways, presumably trying to pinpoint any inconsistencies and get to the bottom of what he obviously suspected to be some sophisticated and totally out of character practical joke. Given that the alternative was to believe something that any rational person would consider impossible, well, it was understandable, but that didn't make the repeated question less irritating.

"Yeah, DiNozzo. That's what I'm tellin' you. You can keep on askin' and askin', or you can walk for-" he glanced at his watch "-about ten more minutes, and see for yourself."

Truth to tell, if they never reached the other door and he had to turn round and go back and claim he was just kidding, he'd be pretty grateful. The last dose of weirdness had been enough to last for a lifetime.

Eventually the tunnel levelled out and then they came to a familiar set of steps with a door at the top. Gibbs noticed that this one no longer had an iris scanner, and was a solid oak door that looked at home in the thick stone of the wall. Last time round, the door had been more appropriate to an evidence garage than a castle. Presumably the Room of Requirement no longer thought he required the comfort of familiarity.

Gibbs waited till all three of them had reached the top of the short flight, then tried the door. It swung open without resistance. Looking back at his agents, he motioned for them to follow him, keeping an eye out for bogies.

It seemed unlikely they'd come across anything too dangerous - last time it had been an autopsy suite. Admittedly, one that looked like it was from some strange mediaeval fantasy game. Under the circumstances, though, he had no confidence that anything would be as he remembered. He wasn't taking any chances.

He was right to doubt. The room turned out this time to be full of old fashioned coat racks and hat stands, complete with various overcoats, boots, and hats. He paid as little attention as possible to the robes (there really wasn't another word for the flowing garments, especially one rather grand one which had galaxies and solar systems embroidered all over it). They were too peculiar for comfort.

He tried to ignore all the pointy witch and wizard hats too, concentrating on the woolly bobble hats and sturdy winter boots. A glance through the window confirmed that it was winter outside, even though back in DC it was late spring and positively balmy. _Best not to think about that._

Dumbledore had claimed this room changed depending on the user's need. Assuming he had meant it literally, that meant they needed... some kind of closet? Or... Hogwarts was a school, so... a cloakroom?

It didn't make a lot of sense, but then, he hardly expected it to by now. At least there was nothing overtly hostile or threatening in here.

Tony and Ziva were looking around, bewildered.

"What is this place?"

"So you really weren't kidding, boss."

They both sounded almost fearful - not an emotion he usually associated with either of them. Probably a good sign in this situation, he supposed. If they weren't a little freaked out by this, _then_ he should worry.

"It's Hogwarts." He shrugged. It was no explanation at all, but he'd already told them everything else he knew.

They quickly searched the room, discovering nothing more suspicious than odd socks and sweet wrappers. There was a door which evidently led into the main part of the castle. Since there was nothing of interest in here, that seemed like the next logical move.

With the ease of long practice, they formed up by the door, then stepped outside in unison, sweeping their guns and searching for danger. Then, as one, they lowered their weapons.

The corridor was full of children.

Gibbs guessed they were in their early teens, and they were inspecting the newcomers and their weapons with interest, but no fear.

Much as he liked kids, this was not what he'd expected to find. Ziva was looking at him with questioning eyes, and all he could do was shrug yet again._ Your guess is as good as mine_, he wanted to say.

He glanced over at Tony, who was staring wide eyed over Gibbs' shoulder.

"Tony!" His agent didn't flinch at his sharp tone - didn't appear to have even heard him. Gibbs suppressed a sigh as he turned to see what had got Tony so transfixed. Then for a second he felt like his heart might stop.

"Kate."

* * *

A/N: I know a few people who will be pretty thrilled by the second AU ;) hope this chapter works for everyone, it took me a long while to get it figured out.


	4. Chapter 4

**_ZIVA_**

The woman gave them a polite but slightly fixed smile, her eyes darting from one to the other of them, clearly confused. Tony was stunned and Gibbs looked like he was about to have a heart attack, so Ziva stepped forward.

"Ziva David. NCIS."

"Hello. Um." She shook Ziva's hand briefly. "I'm Caitlin Gibbs."

That was an odd coincidence, admittedly, but still not a good reason for the strangled noises from her colleagues. Though Gibbs had also called her Kate...

"Kate?"

Her forehead creased. "No, just Caitlin. No one calls me Kate."

"And you are...?"

"I'm a teacher here." Caitlin looked at her as if that was a stupid question. Given the cluster of children surrounding them, maybe it was.

She sounded more or less English, which made sense after what Gibbs had told them in the tunnel, but to Ziva's well trained ears there was the trace of an American accent in her voice.

"What's NCIS?" She seemed suspicious. Ziva couldn't blame her. Three people appearing in the middle of a school was probably no less strange to her than finding the door and the tunnel had been to them.

"Naval Criminal Investigative Service."

Ziva had long since grown accustomed to no one recognising the acronym, but she was also used to people reacting to the explanation with fear and mistrust. Just occasionally a sailor in a tight spot who was in need of an advocate would be relieved to see them, but usually the most positive reaction they got was indifference.

She had never experienced this reaction. Caitlin's eyes had lit up.

"Naval? You're with the navy? The American navy, obviously. You're muggles, aren't you? Wonderful!"

_Not_ another _peculiar idiom._ She sighed. "I do not know what a muggle is, but we are federal agents."

Caitlin laughed. "Muggles are non magic people. I teach muggle studies. Minerva suggested we might try to forge some links with muggle government agencies who could be trusted not to overreact. I never thought she would get permission to do it! You're here for my class?"

Ziva just stared. Caitlin obviously thought she'd explained everything, but if anything it had just made it all seem even stranger. She looked at Tony, who pulled his best 'How the heck should I know?' expression, then at Gibbs, who was still looking like he'd been hit by a freight train. No help there.

"I... I do not really... That is, I did not know..." She really didn't have a clue what to say. Perhaps this woman was mentally unstable. Or perhaps they all were. Or perhaps this was a dream from which she would wake up at any moment. If she was lucky.

Caitlin looked a little perplexed by their reactions. "Maybe I should go and find Professor McGonagall. Who asked you to come here? Was it the headmistress?"

"Dumbledore."

It was the first word Gibbs had said since he'd called this woman Kate, and his voice still had the same strained, breathy quality. The woman turned to him, and Ziva would've sworn that Gibbs actually paled slightly under her gaze. Caitlin frowned a little, though the expression was sad rather than angry.

"You knew Dumbledore?"

There was a pause. "Knew?"

Caitlin put a hand to her mouth as realisation dawned. "Oh. Oh, I'm so sorry. I thought... I didn't realise. He was killed."


	5. Chapter 5

**_TONY_**

There was something telling about the way she said it - not simply 'he died'... but not 'he was murdered', either. She didn't elaborate, and Tony wondered what exactly that meant.

"I thought everyone connected with Hogwarts knew." She bit her lip, then visibly gathered herself together, putting on her 'teacher' face. It looked a lot like Kate's 'agent' face, he thought.

She turned to her class, and sent them off to 'Hufflepuff' in the basement - whatever that meant - then gestured for the NCIS team to follow her into a nearby classroom.

Tony got the impression that Gibbs was relieved to sit down, or at least that his body was grateful not to be propping him up any more. He hadn't seen Gibbs look this bewildered in a very long time.

It didn't help much when she drew a smooth, shiny wand from her belt and gestured to the door, muttering something under her breath. Tony wasn't entirely sure he wasn't imagining things, but he could've sworn there was an odd, slightly squelchy noise, as if the door had just sealed itself.

Once they were settled, Caitlin continued. "There was... Well, it would take too long to explain. It was hard for the whole wizarding world, it took them a long time to get back on their feet. But Minerva is headmistress now."

"They?" Trust Ziva to pick up on a small inconsistency. Well, it probably helped that she wasn't dealing with the shock of seeing a long dead colleague apparently resurrected. "It was hard for them? Wasn't it hard for you, too?"

"Well, yes, I suppose I-"

"You suppose?"

"I don't remember-"

"How could you _not_ remember such a significant-"

"Ziva!" She was going to go into bulldog mode if they weren't careful, and if they were going to get answers out of K- out of this woman, then bullying her probably wouldn't be wise.

Ziva subsided, though she didn't look at all happy. Tony gave her a pleading look and then continued the interrogation more gently.

"Why don't you remember, K-Caitlin?" His voice tripped over her name. The urge to call her Kate, to start picking at her and teasing her, to slip back into that same old easy, spiky familiarity... It was like some twisted torture.

He couldn't help thinking that Kate, if the old Kate could see him, she would find his discomfort hilarious and well deserved.

The question obviously troubled her. The only time Tony had ever seen Kate - _their_ Kate - quite this unsettled was when she'd shot a man who turned out to be innocent. "I'm sorry if this is hard." Apologising to a- well, she wasn't a suspect, but still. "We're just trying to work out what's going on."

She nodded. "I'm sorry. It's just a little complicated. I don't know why, you see. I-" She shrugged and the uncertainty on her face was now clouded with something darker and sadder. "I was... found. I don't know what happened." A small smile, and not a very convincing one. "All I could remember - all I've ever remembered from before Hogwarts - was my name."

"Caitlin Gibbs?"

She looked at him like he was a little slow, and the expression was so familiar it was almost painful. "Yes, Caitlin Gibbs. I don't mean to be rude, but why do you keep asking my name?"

Tony risked a glance at Gibbs, who was still a decidedly funny colour, and decided that maybe tackling this a little at a time would be a good idea.

"It's just... Well, you look like-" _understatement of the century_ "-a woman we worked with. And her name was also Caitlin. Except she almost always went by Kate." _And by the way, she's dead. And also you could be her twin sister. And when she died Gibbs - no relation, strange huh? - went a little crazy for a while. _No, no need to freak her out by piling on all the weird in one go.

"Oh. Oh, I see."

There was a pause while she digested that.

"Is it... possible that you have- you know, normal- I mean, muggle relatives or family?"

"I- I really don't know. I'm sorry." Tony shook his head sympathetically at her repeated apology, but didn't interrupt. "All I know is that someone found me, and brought me here. The healers looked after me, and I had no other home to go to. Then I started helping in classes, and when the old teacher retired, I took over Muggle Studies. No one else was interested in teaching it, and I love it."

"How long have you been here, at Hogwarts?"

She thought for a moment. "Six years - or maybe closer to seven, now." Not long after Kate died, he couldn't help but notice. "It took a while for me to- well. I was a little lost, when they found me. Madame Pomfrey was so kind... When I got better, and no one could find out where I was from, it was natural to stay here at Hogwarts."

"And you ended up teaching?" It might be important to know just how that panned out, but Tony found he was also genuinely curious. It was strange to imagine Kate, or at least a near perfect facsimile of Kate, as a schoolteacher. It seemed such a sedate career, so unlike something Kate would choose. Though Caitlin seemed to be softer, gentler than the Kate he remembered.

A shrug and a rather more genuine smile than they'd seen from her so far. "Spending time with the children... it helped me come back to myself. And I found out that I was good with them. I enjoy spending time with them, they like me... I suppose maybe I used to be a teacher."

"And you teach 'Muggle Studies'?" Ziva sounded incredulous. Tony could almost hear the air quotes dropping into place around the words.

"I've been fascinated by muggles for as long as I can remember-"

"Which isn't very long, right?" Tony hadn't really thought that question through. The glare she shot him was vintage Kate. _If looks could kill._.. He smiled a little. "Sorry. That was a little insensitive."

"You think?" Man, she even had her Gibbs impression down pat. Even though she'd heard all of three words from the man.

At least it seemed to have snapped her out of the funk that their unanswerable questions had provoked. Her business face was back, and she looked around at them, suddenly curious and a little concerned.

"Who are you people, anyway? And how did you get here, if Minerva didn't arrange this? Muggles can't even see Hogwarts from the outside, and there are enchantments- are you really muggles? I should go and see the Headmistress, this can't be good, I-"

She started to get up from her chair, and Tony laid his hand firmly on her arm. The old Kate would never have let him stop her that way - he'd have lost a finger - but the contact was enough to make Caitlin pause and look him in the eye.

"Kate- Caitlin-" _Damn name _"-we are, uh, muggles. We don't really know how we ended up here, but we are government agents. We're used to keeping secrets, and we're used to keeping people safe."

He felt the tension leave her as she subsided. She didn't look quite convinced, but Tony couldn't help thinking that if the situation were reversed, he'd be freaking out far worse. So far, she'd taken this remarkably well.

"As for who we are, well, I'm very Special Agent Anthony DiNozzo - you can call me Tony. This is Special Agent Ziva David, I still call her Probie but she's not any more, so I recommend you stick with Ziva because she's dangerous."

Caitlin looked over in alarm at his tongue in cheek warning, and Tony almost laughed. It felt so normal, in a very abnormal way, to be sitting here with her. He'd forgotten to temper his sense of humour. "Don't worry, she's well trained, she won't bite," he added, earning himself a scowl from Ziva. "And he-" _yes, that guy who's looking at you like you're a ghost_ "- is Gibbs."

"Gibbs?" That got her attention.

"Yeah, weird, huh?"

"Yes..." For a moment it almost seemed she was about to say something, but instead she just turned towards Gibbs, her eyebrows drawing together in concentration as if she was trying to dredge her memory for his face.

Gibbs held her gaze for a few moments, then looked away and - _holy crap_ - was the boss blushing, just a little?

"So," she said at last. "Now you know who I am and I know who you are... What I'd really like to know is what are you doing here?"

"That's-" he laughed "that's a good question, Caitlin. A really, really good question. And I don't have an answer right now."

Gibbs finally spoke up. "Last time, it was Dumbledore needing help with a crime - a murder. He needed a team who could process a crime scene."

She thought about that for a second, then nodded firmly. "I think- I think we should go to see the headmistress."


	6. Chapter 6

**_GIBBS_**

Gibbs wasn't sure what 'neeps and tatties' were, and couldn't imagine why such a strange phrase might be used as a password. Given how surreal this day had already been, though, random words given to a talking gargoyle who then moved aside to reveal a moving staircase in stone? That was probably one of the less strange things he'd seen in the last hour or so.

"So now the Room of Requirement is recruiting staff for us? When Dumbledore wakes up I shall be having words with him. He should have told me about their visit."

McGonagall had received the news that three strangers from an American federal agency had turned up in the cloakroom with a mixture of emotions, largely annoyance and anger, but hadn't seemed the least bit surprised.

Caitlin actually laughed. "It was years ago." That little snippet had given the team a shock when they had figured it out. It had only been a few months for Gibbs - in Hogwarts it had been twenty years since the team was last here. "Even Dumbledore couldn't have known they would ever come back, Minerva!"

McGonagall looked - well, the best word Gibbs could think of was pissed. "He should have known better than to dabble in time magic. There's a reason we don't do that sort of thing," she grumbled. "And at the very least he should have told me the Room had done this before. Heaven knows what mischief could have been caused..."

Apparently a building or room (he wasn't clear whether the blame lay with the Room of Requirement or Hogwarts as a whole) acting autonomously was an irritation. A fairly major but not particularly unexpected one. Caitlin, now she'd gotten her bearings, didn't seem at all fazed by McGonagall's umbrage. She was smiling sweetly, radiating calm and certainty.

Gibbs was fairly sure he would've preferred it if either of them were at least mildly shocked, and found himself wishing again that they'd brought Ducky along. Caitlin's soft coaxing rather reminded him of the old man and his gentle but razor sharp wisdom and insight. The ME's equanimity the last time they had visited the school had been oddly reassuring.

As for talking about Dumbledore waking up... He didn't even want to go there. There was no possible meaning that he could think of for waking up a dead man which seemed remotely like something he wanted to witness. He'd explained his job to his dad as the dead telling stories, and he was aware that Ducky regularly had conversations with the bodies in his care, but in this place he had no confidence they weren't talking quite literally.

"This is most irregular."

The headmistress seemed like a woman who wouldn't tolerate any kind of nonsense. She was obviously relatively elderly, at least by normal standards, but it didn't seem to be slowing her down much. Maybe it was different for wizards. She was - he rummaged in his brain for the right word, then smiled to himself when he found it - spry. She would get on well with his father.

"We did talk about letting the children meet some real muggles, Minerva." That was Caitlin, her voice quiet but persuasive. He got the impression that this was a tried and true method to convince McGonagall, and also that not everyone got to call her by her first name.

"Well. Well." She huffed a little, but even someone with considerably less skill at reading people than Gibbs could've seen that she was weakening. He found himself wondering if Caitlin had somehow inherited Kate's profiling skills, then shook his head at the ridiculous thought.

"Well. I suppose you had better introduce me to these people, Caitlin. Then we shall see what can be done."

Once introductions had been made, he was entirely happy to sit back for once and let DiNozzo handle the details. Words floated back now and then towards the couch he'd settled on - things he understood, like Tony's explanation of the agency, the headmisstress's insistence that any contact must be under a condition of complete secrecy, and other, practical things.

There were other things, however, that made no sense at all, like ravenclaw, slytherin, ministry of magic, fidelius charm. He hoped Ziva's usually excellent memory worked as well under completely bizarre circumstances as it did under dangerous ones. She and Tony would definitely be doing the heavy lifting today.

The office was full of interesting things to look at, while his brain attempted to process all the weirdness. Several of the walls were lined with thick, well bound books. Some of the titles were fascinating, but then he got to _Accidental Amputation in Apparition: Splinching - Causes, Cures, and Limb Reattachment_, and decided he'd rather not know.

Over in a corner was what appeared to be a bowl that in other circumstances he would've said contained dry ice and some sort of light show, but that seemed unlikely here. Behind the headmistress he noticed a portrait of Dumbledore. It was one of the few things in the room that held any familiarity, though, strangely, the artist had painted him asleep. It took Gibbs a while to realise that the painting also appeared to be breathing, a realisation that rather appalled him. It did, at least, give a slightly less disturbing connotation to the idea of waking the wizard up.

Then of course, there was Kate - or rather, Caitlin. His gaze kept returning to her, and although in looks she was entirely familiar, she was the thing that worried and confused him the most. She was enough like the Kate he remembered for it to completely frazzle his brain, and different enough that he didn't know how to even start figuring out the connection between the two women. There had to be one, that was certain. There was no way in the world that this could be a coincidence, even if he had believed in coincidences in the first place.

The fact that the surname she had 'remembered' for herself was Gibbs... He didn't know what to make of that, what it meant - whether it meant anything at all. McGonagall had noticed he had the same name, he had seen her react, but to his relief she hadn't made any comment. He wouldn't have known what to tell her.

Kate had always held a kind of fascination for him, intriguing and infuriating him in equal measure. She would challenge him, sometimes more even than Tony did, with that self confidence and even swagger that had first caught his eye on Air Force One. She'd stood her ground, dared him to overlook or dismiss her.

Then at other times she would allow a case, a witness or a suspect to get so deep under her skin that she seemed to regress to being an uncertain, insecure little girl who was desperate for approval. For his approval - seeking validation, not yet able to know for herself when she'd done a good job.

He'd been hard on her, wanting to help her grow into the agent his gut told him she could be, and the thought that the most sincere compliment he'd ever given to her had been seconds before she died... that had haunted him. Losing an agent (a colleague - a friend) was never easy, but it had happened so suddenly; a rare moment of triumph turned sour in a split second.

It didn't help that he had never been able to work out how she had felt about him. Heck, he hadn't been able to pin down how exactly he felt about her. He wasn't one for what ifs, but a treacherous part of his mind sometimes wondered... suppose he'd asked for her phone number instead of offering her a job?

Caitlin was... well, she didn't seem as headstrong or bossy as Kate could be, but there was a strength in her quietness, and it was clear she knew how to convince people to her point of view. Something about her suggested she was grounded and secure in a way Kate was not. For a woman who knew so little about herself, who only had a name and a few years of memories as a foundation, she seemed remarkably at peace.

She was also just as beautiful as he remembered Kate being; an expressive mouth, dark, liquid eyes, deep dimples that appeared when she smiled, soft, wavy hair that gleamed auburn when it caught the light.

He found himself staring at her again, and forced himself to look away, though he heard her footsteps approach and was painfully aware of her proximity when she perched on the edge of the couch seat next to him.

For a short while she sat in silence, and Gibbs allowed himself to relax a little. Then suddenly she startled him with a question.

"What was she like?"

He looked at her without actually facing her. "Who?" It was a good assumption she was asking about Kate, but he kind of hoped she wasn't. At least asking for clarification gave him a few moments grace.

"Kate. This woman who looks like me."

"Looked."

She shut her eyes briefly. "Looked like me." Her tone was apologetic.

"Uh..." He floundered, wishing she would have this conversation with someone, anyone else but him. _Serves me right for leaving Tony to sort this out._

"Please, Agent Gibbs." It felt strange to hear her address him so formally. "I have no family, no home except Hogwarts. You can understand why I am curious." Her voice was soft, persuasive, and out of the corner of his eye he could see the pleading in her eyes.

"She was..." How the heck was he supposed to describe Kate to her? To talk about Kate to someone who practically _was_ Kate? "Stubborn. Persistent. A pain in the ass." He laughed. "She had Tony round her little finger, and she knew it. Tim too. Great shot. Ballsy. Argumentative. She could be funny. Brave - she was on the President's Secret Service detail before she came to NCIS." He hadn't realised he had so much to say. He took a deep breath as snippets of memory swirled in his mind.

"She really cared, about the team, about... Tried to get me to open up a time or two." He always wished he had somehow told her thank you for trying, let her know he'd appreciated it more than he had ever admitted. "Put her life on the line for others. She took a bullet for me." Two, really, but thinking about that still hurt. "We miss her still. She had beautiful eyes..." He trailed off. Somewhere along the way he'd instinctively turned towards her, and her cheeks had flushed pink at the compliment.

"Thank you," she murmured. He had no idea if the thank you was for that or for satisfying her curiosity about Kate. He had no idea where the compliment had come from, either, though it was certainly true.

"She was a good agent. A good person."

She nodded, looking down at the string of red beads she was turning over and over in her fingers. He got the impression it wasn't nerves, but more something to focus on as she thought about what he'd said. The beads reminded him of something, though he couldn't pin it down. They were a little old fashioned, not really the kind of jewellery he could imagine Kate wearing.

"Why do you keep looking at me like that?" she asked suddenly.

He frowned. "Like what?" He had been looking at her - _studying_ her - almost couldn't help it. He'd noticed Tony having the same problem. She was Kate but she wasn't, a riddle they couldn't yet solve.

"Like..." She shook her head, and her blush deepened. "I don't know."

_Oh. Like that_. He'd gotten quite good, way back when, at not looking at her like he could swallow her whole, but he was a few years out of practice now. "Sorry." It came out without a conscious thought, and then he laughed.

"What's so funny?"

"You always did make me want to break rules."

She raised an eyebrow at him in a Kate type way, and it was both achingly familiar and long missed. "Break rules?"

He sighed and shook his head. "Long story. I- well... maybe another time."

"So, do you think you- you might... come back?"

She sounded wistful, but also a little embarrassed to be asking. He allowed himself to smile at her. "I hope so, Caitlin. I sure hope so."


	7. Epilogue

_**TONY**_

As they made their way back towards the Navy Yard, Tony found himself shaking his head. Even walking through a tunnel for which he had no explanation, illuminated by flames that were probably magical, towards a door that should not exist, he still couldn't quite believe what had happened.

In his hand was a sheet of paper - well, no, parchment, really - covered in emerald green ink detailing NCIS's involvement with Hogwarts. They had means to get in contact with McGonagall, and several suggestions for alternate methods of travel - she had been most understanding once they'd explained the kind of attention doors magically appearing in federal buildings might attract.

He was even kind of looking forward to coming back to visit, meeting the kids (he'd been relieved to find that there were no small children at the school), maybe getting to know the new version of Kate - and yet, if he woke up and found out it was a dream, or Gibbs told him this was some elaborate hoax... He'd probably find that easier to believe.

Gibbs didn't look like a man who was about to yell "Gotcha!" any moment. In fact, the whole way back he'd been quiet - even for a functional mute. Seeing Kate again (Tony wasn't sure he'd ever get used to calling her Caitlin) had been a shock, sure (OK, huge, ridiculous understatement), but he had been surprised at the effect it had had on the boss. That was a little puzzle it might take a while to figure out.

He took another look at the... paper, parchment, whatever in his hand. He couldn't help noticing that Abby, McGee, Ducky, even the autopsy gremlin... They were all neatly listed, accounted for. He remembered McGee's odd behaviour, just a few hours ago when the world had made sense. How they'd all kept it a secret for so long... Except, of course, no one in their right minds would have believed it.

That could make life interesting. McGonagall had insisted the director be informed, and Tony was torn between wanting to be a fly on the wall for that particular meeting, or wanting to go far, far away and stay there. For a long time. Maybe forever.

He was so busy with his thoughts that they reached the American end of the tunnel (he didn't even want to think about how that worked) before he expected it. Stepping up and over the lintel, back into normality, was almost stranger than seeing Hogwarts had been. How everything could still look and sound and be the same after today - and yet it did.

Ziva and Gibbs followed him out into the evidence garage, and Tony was opening his mouth to ask what they would do about the door when it disappeared without a trace. _Hmmm. Handy, I guess._

He exchanged a glance with Ziva, who shrugged. Gibbs simply stood there, looking at the blank piece of wall wih an expression that Tony didn't even try to name.

"So, I guess we should go... get back to work?"

That seemed to snap Gibbs out of his daze. "You think, DiNozzo?" He was striding towards the elevator before Tony managed to come up with a smart alec response.

"Where're we going, Boss?"

Gibbs turned back as they approached, smiling - honest to God smiling - like  
Tony hadn't seen in a while. He couldn't help but grin back.

"We're taking _that_," he pointed to the parchment, "to Abby's lab." He raised an eyebrow, suddenly looking downright playful. "Then I'm gonna go see a man about a door..."

* * *

_**A/N**: _

_It will probably take a while, so please be patient, but this is not the end of the NCIS/Hogwarts story. Watch this space for the third (and probably last, but you never know ;)) instalment..._


End file.
